What threatens the Objectives of the MPA?

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1b. Surveillance, compliance and enforcement regime effectively detects all known threats to offshore ecosystems

1f. No loss of genetically distinct sub-populations from inshore or offshore areas

Description: Licensed commercial fishing by the international longline tuna fleet ended in Ascension’s waters in April 2019. However, vessels are known to undertake illegal, unreported and unregulated (IUU) fishing for tuna and other species such as billfish and sharks in the Atlantic. Some of these vessels may operate in the MPA area (Rowlands et al. 2019). These vessels do not respect quotas or allowable catch levels for targeted fish species nor necessarily employ methods to limit bycatch of non-target species such as sharks, turtles and seabirds. As well as the direct impact on the fished species, removal of large predatory fish will affect the whole marine ecosystem including seabirds that take advantage of tuna forcing their flying fish prey close to the surface.

Assessment of scale of threat: Over the past four years, satellite surveillance using Synthetic Aperture Radar (SAR) detections and vessel Automatic Identification Systems (AIS) have detected a small number of incidents of suspected IUU fishing within the Ascension EEZ.

High confidence SAR detections that did not correlate with legal vessels transmitting AIS signals in Ascension’s waters between 1^st January and 31^st March 2017. These could be ‘dark vessels’ operating illegally.

By analysing satellite data and other available intelligence, a Blue Belt Programme risk profiling exercise has assessed the current IUU risk for Ascension as ‘moderate’ and present all year round with a peak in January and February (Thomas et al. 2018).

Species/habitats at risk:

Targeted in fishery - bigeye tuna, yellowfin tuna, blue shark, Atlantic blue marlin, wahoo

Bycatch and ecosystem effects - pelagic waters around seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, green turtle, Ascension frigatebird, sooty tern, Galapagos shark, silky shark, humpback whale

Predicted future trend: Improved surveillance and more effective enforcement coupled with a contracting market are likely to reduce IUU fishing for tuna in the Atlantic.

Legislation:

Fisheries (Conservation and Management) Ordinance, 2015.

ICCAT regulations

Actions: Prevent illegal offshore fishing

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1f. No loss of genetically distinct sub-populations from inshore or offshore areas

Description: Though no licensed large-scale commercial fishing now occurs in the MPA, tracking studies have shown that species such as tuna and marlin migrate over large distances (http://asios.cles.ex.ac.uk/) and so could be caught by fishing vessels outside of the MPA. This means legal longline fishing in the mid-Atlantic outside of Ascension’s MPA could also affect biodiversity within the MPA.

The Atlantic longline fishery predominantly targets bigeye tuna, but also takes yellowfin tuna, blue shark and billfish species. A purse seine fishery also operates in the eastern Atlantic targeting tuna species (Pascual-Alayón 2019).

Plot of target and bycatch species weight as a proportion of total catch weight in the longline fishery operating in the mid-Atlantic 2005-2014 (data supplied by ICCAT). Each square represents one percent of the catch.

Assessment of the scale of threat: All of the species caught in the fishery range widely across the ocean and quotas are set at a regional level by International Commission for the Conservation of Atlantic Tuna (ICCAT). Based on the most recent data available, ICCAT have made the following assessments of stock health for the species that form an important part of the Ascension MPA fish fauna:

As of historical poor management of fisheries in the Atlantic are very evident with all the species except yellowfin tuna considered to be overfished. Further improvements in regional stock management are required since only yellowfin tuna and Atlantic swordfish stocks have current fishing levels that are thought to be sustainable.

There is also a small risk of bycatch of other shark species, turtles and seabirds, though they are rare in catch records in the Atlantic tuna fishery (Huang 2010). Some seabird species take advantage of small fish forced to the sea surface by tuna and other large pelagic fish as they feed. It is not known how reliant the seabird species found in Ascension’s MPA are on this association nor how big an impact the longline fishery outside of the MPA will have on tuna foraging activity within it.

Species/habitats at risk:

Targeted in fishery - bigeye tuna, yellowfin tuna, Atlantic blue marlin, wahoo, blue shark

Bycatch and ecosystem effects - pelagic waters around seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, green turtle, Ascension frigatebird, sooty tern, Galapagos shark, silky shark, humpback whale

Predicted future trend: To date, ICCAT has not implemented the measures recommended by its scientific committee to reduce catches to sustainable levels. In the short-term the threat of legal commercial fishing in the wider Atlantic will remain unchanged.

Legislation - ICCAT regulations

Actions: None

Threatens achievement of Objectives:

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

2a. People living on Ascension have access to recreational and fishing opportunities in the MPA that are equitably shared and enjoyed by the community

2b Fishing pressure in inshore areas is adaptively managed by local stakeholders to prevent it contributing to the decline of any stock

2c Ecological relationships between harvested, dependent and related species are maintained in inshore areas

2d. Ascension is recognised as a world leader in the responsible management of sports fishing and ecotourism; these activities have no negative impact on the behaviour or population size of protected species

2e. A significant proportion of revenue from sports fishing, ecotourism and other economic activities in the MPA is retained on the island

Description: Fishing for food and recreation is an important part of local culture and is carried out by people living on Ascension and visitors to the island. This can take place from both the coastline and from small boats that don’t generally go further than 5km from the coast. The main species caught are yellowfin tuna, rock hind grouper, moray eel, wahoo, spiny lobster and octopus. A well-managed, recreational fishery will be part of a successful MPA, but fishing that is not properly regulated could threaten the MPA’s objectives.

Most of the fish species being exploited are apex predators. As well as the direct effect on the fished species, studies from other coastal areas suggest their selective removal will almost certainly have effects on the wider ecosystem. Non-target species are caught in the recreational fishery particularly Ascension frigatebirds and Galapagos shark. There is a high degree of awareness amongst the fishing community that these species are protected, but the unhooking process can be damaging. The discarding or loss of fishing gear can also impact on other marine species and this is covered in more detail in the pollution section.

A poorly-regulated recreational fishery also threatens the socio-economic objectives of the MPA as it does not ensure current exploitation is sustainable and that the same fishing opportunities will be available for future generations.

Assessment of the scale of threat: Fishing pressure on Ascension is constrained by the small size of the island population and limited routes for export, but that doesn’t prevent all risk of damage to inshore fish stocks (Choat & Robertson 2016; Armstrong & Reeves 2015). The isolation of Ascension and limited area of shallow water habitat means that some fished species may have little capacity for replenishment if stocks are severely depleted around the island. No endemic species are targeted in the fishery, so this threat is unlikely to result in species extinction but could cause local extinction.

We currently have little data on the number of fish being caught and addressing this is a high priority for the Inshore Fisheries Advisory Committee. Some sense of the amount being caught is provided by the filleted weight of fish being sent to friends and family living in St Helena, the US and UK, which is recorded through the export permit system and shown in the table below. The reduction in export routes from the island in 2018 caused by the decrease in vessel movements between Ascension and St Helena and the suspension of the South Atlantic Airbridge is clearly reflected in the data.

The weight of tuna and wahoo exported is negligible compared to commercial quotas exploiting the same Atlantic populations. The five year mean export of estimated whole weight of yellowfin tuna was 7.5t per year between 2014 and 2018, with a peak of 15t in 2015. For comparison, the quota for Atlantic Yellowfin tuna set by ICCAT is 110,000t for 2020. Recreational fishing will have no impact on the overall yellowfin or wahoo populations, but any local depletion around Ascension could reduce feeding opportunities for seabirds that depend on predatory fish forcing flying fish closer to the surface.

The recreational fishery has greater potential to affect shallow water species such as rock hind grouper and glasseye snapper simply because these are isolated populations. There is no evidence the fishery is having an impact but we currently don’t know what level of fishing is sustainable. This will be addressed by the IFAC and the Monitoring, Evaluation and Research Strategy.

We currently have no information on the wider ecosystem effects of the recreational fishery nor the level of bycatch of species such as sharks, turtles or seabirds.

Species/habitats at risk:

Targeted in fishery- rock hind grouper, moray eel, spiny lobster, glasseye snapper, common octopus, yellowfin tuna, Atlantic blue marlin, wahoo, rainbow runner

Bycatch and ecosystem effects - green turtle, Ascension frigatebird, sooty tern, Galapagos shark, silky shark

Predicted future trend: The introduction of an inshore fisheries management system on Ascension would bring about a substantial reduction in this threat as monitoring and a suite of potential management measures are put in place to guard against any over-exploitation.

Legislation:

Fisheries (Conservation and Management) Ordinance, 2015.

Wildlife Protection Ordinance, 2013.

Customs Ordinance, 2002

ICCAT reporting of recreational fishery

Actions: Regulate and manage inshore fisheries

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

2a. People living on Ascension have access to recreational and fishing opportunities in the MPA that are equitably shared and enjoyed by the community

2b Fishing pressure in inshore areas is adaptively managed by local stakeholders to prevent it contributing to the decline of any stock

2c Ecological relationships between harvested, dependent and related species are maintained in inshore areas

2d. Ascension is recognised as a world leader in the responsible management of sports fishing and ecotourism; these activities have no negative impact on the behaviour or population size of protected species

2e A significant proportion of revenue from sports fishing and ecotourism is retained on island

Description: Sports fishing is defined here as a commercial operation where the primary purpose is the experience of catching fish and where the fish caught may either be consumed or released following capture. In practice, the dividing line between this and recreational fishing is not always clear and the same boat can take friends and family on a non-commercial basis as well as paying customers. At the extreme, however, are dedicated businesses that have charged international clients £1000s for the opportunity to fish around Ascension.

The main species targeted in the fishery are yellowfin tuna, blue marlin and wahoo. The fish are taken by rod and line or spearfishing on SCUBA. The removal of such apex predators could have wider ecosystem affects and there is a risk that non-target species such as Galapagos shark, seabirds and green turtle will be hooked by rod fishermen.

Large sports fishing vessels have the capability to fish beyond 12NM of the island, which is illegal under the Fisheries (Conservation and Management) Ordinance, 2015. If such trips do occur they are likely to concentrate effort around the shallow water seamounts where the density of their target species, tuna and marlin, is higher than in the surrounding ocean.

Sports fishing could be a valuable source of income to the island, so poor-management of this resource would also threaten the social and economic objectives of the MPA.

Assessment of the scale of threat: The threat from sports fishing is currently low since all three companies that previously offered this activity on Ascension ceased to operate when the South Atlantic Airbridge was suspended in 2017. Resumption of direct flights to the UK is likely to increase demand for this service once more.

Historical catch data from the Ascension sports fishery are patchy. The most complete data come from 2008 when four vessels were licensed and catches from a total of 28 boat days were recorded (there are no records of days when nothing was caught). Yellowfin tuna were the most commonly caught species and there was a high rate of catch and release particularly for billfish.

Yellowfin tuna, wahoo and dorado migrate over large distances and, based on current knowledge, fish in the Ascension MPA are part of a wider Atlantic population that is fished by the commercial longline fleet. In that context, the Ascension sports fishery is negligible compared to the total allowable catch of these species set by ICCAT for the whole Atlantic.

The catch and release of billfish is practised by most operators and would be required under new guidelines for anything other than record attempts. Estimates of post-release survival of billfish vary widely based on hook type and study design, with published survival rates ranging from 65% to 100% (Pepperell and Davis 1999; Domeier et al. 2003; Graves and Horodysky 2008).

There are no figures available for rates of bycatch in the sports fishery, but hooked Ascension frigatebirds and Galapagos sharks are frequently reported. These are released, but it is not always possible to remove hooks or avoid distress.

Species/habitats at risk:

Targeted in fishery- yellowfin tuna, Atlantic blue marlin, wahoo

Bycatch and ecosystem effects - green turtle, Ascension frigatebird, sooty tern, Galapagos shark

Predicted future trend: Sports fishing will increase on Ascension with the expected restoration of direct flights to the UK and the marketing of the island as a fishing destination. However, the introduction of a licensing system, regulations and guidance will substantially reduce the scale of this threat.

Legislation

Wildlife Protection Ordinance, 2013

Business permit policy

ICCAT reporting of recreational fishery

Actions:

Regulate and manage inshore fisheries

Guidance and regulations for sports fishing and ecotourism

There is great uncertainty about the impact climate change will have on our oceans. However, the model of fixed, area-based protection in open pelagic environments is clearly going to be severely challenged by climate change as mobile species alter their distribution to reflect conditions (Tittensor et al. 2019). A shift in regional ocean currents or decline in primary production could result in the Ascension MPA protecting a relatively barren area of ocean. The greater abundance and diversity of marine life we currently see associated with the island and shallow water seamounts may be less likely to shift since they are connected to these fixed topographical features. However, the corollary of this is that the absence of anywhere to migrate to makes these communities vulnerable to extinction if conditions change too profoundly or rapidly for species to adapt to them.

Climate change also has the potential to interact with other threats to increase both their likelihood and severity. For example non-native species may be more likely to become established or outcompete native species if there are shifts in ocean currents and changes in prevailing conditions. Pollution from sediment run off will be higher if the frequency of extreme rainfall events increases, and rising sea levels could lead to calls for the development of coastal defences.

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

Description: Much of the increased energy trapped on earth by the emission of climate change gases has been absorbed by the ocean over the past century. The result has been a rise in sea temperatures. The absorption of energy happens initially at the surface of the ocean, but circulation currents and energy transfer means all depths of the ocean have been affected by rising temperatures.

Measurements of water temperature show continuous warming of the oceans at all depths between 0 and 2000m since 2005, and an overall longer-term increase since the mid-20^th century. Fewer data are available for the very deep ocean, but these are also thought to be warming (IPCC 2019). From this starting point, global sea surface temperatures are predicted to rise by between 1 and 3°C by 2100 depending on the reduction in the emission of climate change gases achieved by the international community (Collins et al. 2013).

Species are adapted to living within the range of temperatures they experience. Some species that have evolved in variable conditions have a much wider tolerance range than others, but all will show stress and eventually death if the temperature rises above this range. Certain parts of a species’ lifecycle, such as egg incubation, may be particularly vulnerable to temperature stress. The length of exposure to abnormal temperatures and the speed of change are also important in determining the impact. Organisms may be able to cope with short periods of elevated temperatures or able to adapt if they change slowly, but prolonged exposure and more rapid changes will have a greater impact.

As water temperatures rise, stratification of the tropical ocean is also increasing. This inhibits the normal cycling that mixes nutrient-rich water from the deep ocean into surface waters where photosynthesis can occur and as a result primary production is reduced. Higher water temperatures and less mixing also lead to lower oxygen levels in the surface layers that limits life and can result in dead zones in the ocean. This potentially fatal reduction in oxygen levels can result from long-term increases in temperature or from short-term heat waves, which are becoming increasingly frequent.

Tropical inshore marine ecosystems are thought to be particularly vulnerable to rising sea temperatures due to the limited temperature range they experience naturally (Tewksbury et al. 2008). However, oceanic islands such as Ascension have very narrow coastal shelves and upwellings of cold water from the deep are sufficiently common that inshore species may have some ability to adapt to temperature fluctuations. We know little about the thermal tolerances of marine species on Ascension but tests on four species of marine invertebrates (two echinoids, an ophiuroid and a bivalve) from Ascension suggested that they would survive at least a 3°C rise in sea temperature, though this does not take into account any sub-lethal effects (Morley et al. 2014).

Coral bleaching, where thermal stress kills the algae that provide energy for the coral, is a widely-observed and devastating consequence of rising sea temperatures. Ascension does not have the extensive coral reef systems that are often found fringing other tropical islands, but the coraline algae, sponges and bryozoans that form part of the base of the inshore food webs on Ascension may be equally vulnerable to higher sea temperatures.

Green turtles are potentially vulnerable to rising temperatures on their nesting beaches as both hatching success and hatchling sex ratios are temperature dependent and the Ascension population appears to have little ability to adapt to different temperature regimes (Tilley et al., 2019). However, the depth at which the eggs are buried in the sand appears to insulate them and could reduce any potential impact. Higher temperatures also pose a threat to incubating seabirds and land crabs, but no direct studies have been undertaken on Ascension.

Species/habitats at risk:

Species: green turtle, land crab, Ascension frigatebird, masked booby, sooty tern, rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, Galapagos shark, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, shrimps of the anchialine pools, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan, bigeye tuna, yellowfin tuna, Atlantic blue marlin, wahoo, silky shark, rainbow runner, bluntnose sixgill shark, Lophelia coral, humpback whale, blue shark, flying fish, plankton, vestimentiferan tubeworm, rimicaris shrimp, bathymodiolus mussels, grenadiers.

Habitats: Sandy beaches, coastal plateaus, rocky reefs, sandy substrate, rhodolith beds, intertidal pools, anchialine pools, pelagic waters around seamounts, benthic habitats on seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, hydrothermal vents, lower slopes of Ascension Island and seamounts, flat abyssal plains

Predicted future trend:

Sea temperatures will continue to rise for the rest of the 21^st century

Legislation:

None directly tackles this threat

Actions:

There are no specific mitigation actions available to address this threat directly. Instead, other pressures will either be reduced as far as possible or, in the case of fisheries, managed adaptively to take into account the impact of a changing climate on the sustainable level or exploitation.

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

2a. People living on Ascension have access to recreational and fishing opportunities in the MPA that are equitably shared and enjoyed by the community

2b Fishing pressure in inshore areas is adaptively managed by local stakeholders to prevent it contributing to the decline of any stock

2d. Ascension is recognised as a world leader in the responsible management of sports fishing and ecotourism; these activities have no negative impact on the behaviour or population size of protected species

Description:

The Atlantic Ocean contains a number of major current systems and areas of massive upwelling that determine the physical properties of the water and hence the conditions for life. Ascension’s position on the Southern Equatorial Current means the MPA benefits from the upwelling of nutrient rich waters that form the foundation of entire ecosystems.

A complex pattern of local inshore currents, eddies and upwelling is also seen around Ascension caused by the deflection of larger-scale water movements by the landmass. This affects the temperature, nutrient content and energy of the water in different areas around the coast. Crucially it also determines how well the floating eggs and larvae of inshore species are retained around the island to develop into the next generation.

Climate change will shift the patterns of energy absorption and transfer that help drive these currents, and the melting of ice sheets in the Antarctic and Arctic will cause massive inputs of cold, fresh water that will further alter patterns of water movement in our oceans.

Assessment of scale of threat:

Perhaps the most fundamental threat to Ascension’s marine environment from climate change would be large-scale shifts in patterns of currents and upwelling. Any shift in the Southern Equatorial Current could cause a large and permanent decrease in the productivity of Ascension’s waters with knock on effects for species diversity and abundance. Open water and sea floor ecosystems in the MPA are reliant on the nutrient cycling to support primary production in the surface layers. If changes in current patterns interrupt this cycling then ecosystem functions, species abundance and diversity could all decline rapidly across offshore areas of the MPA, with subsequent impacts on seabird populations.

Most of Ascension’s inshore species have at least one phase in their life cycles where they are at the mercy of local currents. This could be the eggs and sperm of broadcast spawners such as oysters and coral or the larvae of fish, crabs and urchins. All must remain in the narrow band of shallow water around the island to survive. Changes to inshore current patterns could alter current retention rates for the better or worse.

Changes in current patterns could also affect the passive and active migration of animals into and out of the MPA. Turtle migration routes are linked to ocean current patterns (Pixar 2003). Green turtles migrating between Ascension and Brazil should still be able to navigate effectively, but may expend greater energy during migration if current patterns change, potentially meaning they will mate or nest less frequently.

Species/habitats at risk:

Species: green turtle, land crab, Ascension frigatebird, masked booby, sooty tern, rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, Galapagos shark, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan, bigeye tuna, yellowfin tuna, Atlantic blue marlin, wahoo, silky shark, rainbow runner, bluntnose sixgill shark, Lophelia coral, humpback whale, blue shark, flying fish, plankton, grenadiers.

Habitats: Rocky reefs, sandy substrate, rhodolith beds, pelagic waters around seamounts, benthic habitats on seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, lower slopes of Ascension Island and seamounts, flat abyssal plains

Predicted future trend:

Shifts in ocean currents can be expected until at least the end of the century

Legislation:

None directly tackles this threat

Actions:

There are no actions that can be taken to directly tackle this threat. Eliminating and managing other pressures is the only course of action available.

Threatens achievement of Objectives (Links to them):

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

Description: Increased levels of carbon dioxide in the atmosphere lead to a higher absorption rate of the gas by seawater and a resultant lowering in ocean pH and concentrations of carbonate ions. Calcifying organisms such as molluscs, corals and coralline algae will all struggle to construct shells and exoskeletons with the reduced availability of carbonate ions in the water, leading to potentially widespread loss of these important groups (Orr et al. 2005). Other effects of acidification such as coral bleaching and the slowing of metabolic and development rates in marine organisms have also been recorded (Kroeker et al. 2013).

Global assessments suggest the world’s oceans are becoming more acidic at a rate of 0.017-0.027 pH units per decade since the 1980s. Under the worst case scenarios it is predicted that pH will decline by 0.29 units by 2100, causing the ocean to be so acidic that the shells of animals would be corroded in the most heavily affected areas and shell formation would be impaired across the oceans. The rate of acidification is greater than that seen 56 million years ago when ocean pH is thought to have been a major factor causing the mass extinction of benthic marine species seen in the fossil record.

Assessment of the scale of threat

There are a large number of calcifying species that play crucial roles in inshore, pelagic and deep benthic ecosystems and are likely to be vulnerable to ocean acidification. Rhodoliths, coralline algae and bryozoans form the structure of some inshore habitats and the foundation of food chains. Molluscs such as oysters, clams, periwinkles and cowries are abundant in Ascension’s inshore and play a role in clarifying the water through filter feeding and are common prey for fish species. In open water, calcifying planktonic species are important primary producers and a food source for larger species, while deep water corals are abundant in waters 1000m deep around the island and seamounts. All will struggle to survive if pH falls too low for them to form calcium carbonate, with repercussions for entire ecosystems.

Species/habitats at risk:

Species: green turtle, land crab, rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, Galapagos shark, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, shrimps of the anchialine pools, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan, bigeye tuna, yellowfin tuna, Atlantic blue marlin, wahoo, silky shark, rainbow runner, bluntnose sixgill shark, Lophelia coral, humpback whale, blue shark, flying fish, plankton, vestimentiferan tubeworm, rimicaris shrimp, bathymodiolus mussels, grenadiers.

Habitats: Rocky reefs, sandy substrate, rhodolith beds, intertidal pools, anchialine pools, pelagic waters around seamounts, benthic habitats on seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, hydrothermal vents, lower slopes of Ascension Island and seamounts, flat abyssal plains

Predicted future trend:

Ocean pH will continue to fall for the rest of the century

Legislation:

None directly tackles this threat

Actions:

There are no actions that can be taken to directly tackle this threat. Eliminating and managing other pressures is the only course of action available.

Threatens achievement of Objectives (Links to them):

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

Description: Higher temperatures result in the expansion of seawater and the accelerated melting of ice caps and glaciers, which combined lead to a rise in global sea levels. This will cause the inundation of coastal areas and could lead to the loss of existing shallow-water and intertidal habitats if they are not able to migrate landward due to natural or man-made barriers.

In addition to the background increase in sea level there will be an increase in extreme sea level events caused by greater swells and wave heights. This will exacerbate the threat of inundation for coastal habitats and the increased energy in shallow marine habitats could be detrimental as sedentary species struggle to hold on and mobile species could be washed ashore, damaged by collisions or have difficulty foraging and mating effectively.

Assessment of the scale of threat

Global sea levels have risen by 16-21cm since 1900 (USGCRP (2017) and are predicted to rise between 0.43 and 0.84m by 2100 (IPCC 2019). Beyond 2100, sea levels are predicted to rise for many thousands of years even if emissions decline (IPCC 2019). On Ascension, sea level is estimated to have risen by 7cm since 1955 and the rate of rise is forecast to increase in the next 30 years (Woodworth et al. 2012). Extreme sea level events are predicted to become more common and what were once rare storm events could become an annual occurrence by the middle of the century.

Pelagic, sea mount and deep benthic habitats in the MPA will not be affected by sea level rise. Shallow water habitats around the island will be altered, but in many cases the underlying substrate and topography is similar above and below the current sea level and so any rise would not have a large impact if the rate is slow enough for species to shift their distribution. The greater frequency of extreme high swell events would have a more significant effect on shallow water habitats, though the exposed nature of the island means many species are already adapted to high energy environments.

Coastal habitats will see the biggest impact of sea level rise. Sea level rise will reduce the area of suitable green turtle nesting habitat since landward migration of the beaches is limited by roads and pipelines or by natural cliffs.

The anchialine pools are approximately 1m above the current sea level. This is greater than the predicted sea level rise in this century, but higher sea levels combined with storm events could create a surface connection between the pools and the open ocean and allow new species to enter the pools threatening the existing ecosystem and endemic species.

Species/habitats at risk:

Species: Green turtle, land crab, shrimps of the anchialine pools

Habitats: Sandy beaches, sea cliffs, intertidal pools, anchialine pools

Predicted future trend:

Sea levels will continue to rise for the rest of the century and many thousands of years beyond that.

Legislation:

None directly tackles this threat

Actions:

Restoration of turtle nesting beaches

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1g No reduction in the extent or condition of key habitats

Description: Only approximately 800 people live on Ascension, yet there is still a problem with littering on the island and a legacy of poor waste management. Discarded fishing gear is a particular problem with line, lead weights and lures commonly found around the coast. In the past solid waste was deliberately disposed of in the sea close to Georgetown and, though the practice has ceased, this material continues to be washed ashore during high swells.

Ascension is 1,300km from St Helena and 1,600km from its nearest continental neighbour, yet rubbish that does not originate from the island still washes up on its beaches. Waste discarded from vessels is likely to be responsible for some of the material and explains the large amount of polypropylene rope, nets and fish aggregating devices that wash up on the island. However, the water bottles, plastic lighters and shoes could also originate from land and it is not possible to identify the source.

The major impacts of marine litter on biodiversity are through entanglement, ingestion or poisoning. Plastic persists in the ocean for millennia (Andrady 2015) and is a major threat to marine life. Top predators are most vulnerable to plastic poisoning due to bioaccumulation of toxins as they eat contaminated prey. A particular problem is ghost fishing where discarded fishing gear continues to catch animals as it floats in the ocean or sinks to the ocean floor.

Assessment of the scale of threat: Beach cleans have been carried out by AIGCFD every three months since 2017 to assess litter accumulation rates.

Accumulation rates of litter on Ascension’s beaches 2017-2019. Based on total weight of litter recorded along a 100m stretch of beach.

Plastic and polystyrene made up the majority of litter recorded in almost all of the beaches around the island. Drink receptacles predominate with bottles and cans making up most of the plastic, glass and metal categories.

It is not possible to carry out regular beach cleans on the remote beaches on the south coast of the island that receive the prevailing currents, but a single clean near Crystal Bay in November 2019 removed 86kg of plastic waste from one 120m² area of beach.

Marine Litter washed up on remote Crystal Bay on the south east coast of Ascension. 86kg of waste was removed from this beach in 2019.

Discarded or lost fishing line, weights and hooks are found around popular fishing sites on Ascension’s coast. In 2019 a single dive clean at One Hook on the northwest coast removed 35.1kg of lead weights, fishing line and glass bottles. Larger nets and fish aggregating devices occasionally wash up on Ascension’s coast having presumably been lost from commercial fishing vessels.

Plastic items are relatively common in brown booby nests on the Letterbox Peninsula, and plastic has been found within regurgitate pellets from sooty terns at the Wideawake colonies (AIGCFD pers. obs.). No systematic studies have yet been carried out looking at levels of macro and microplastic in the stomachs of marine species around Ascension or the potential impact on this in survival, but this is a priority identified in the Monitoring, Evaluation and Research Strategy. Likewise no targeted monitoring of entanglements is carried out, but reports and photographs of turtles, sharks and other fish species caught in fishing line, nets or other discarded objects are received by AIGCFD.

Species/habitats at risk:

Sandy beaches, coastal plateaus, rocky reefs, sandy substrate, rhodolith beds, intertidal pools, anchialine pools, pelagic waters around seamounts, benthic habitats on seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, hydrothermal vents, lower slopes of Ascension Island and seamounts, flat abyssal plains

green turtle, Ascension frigatebird, masked booby, sooty tern, rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, Galapagos shark, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, shrimps of the anchialine pools, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan, bigeye tuna, yellowfin tuna, Atlantic blue marlin, wahoo, silky shark, rainbow runner, bluntnose sixgill shark, Lophelia coral, humpback whale, blue shark, flying fish, plankton, vestimentiferan tubeworm, rimicaris shrimp, bathymodiolus mussels, grenadiers.

Predicted future trend: Improved waste management, a reduction in single use plastic and better public engagement on Ascension should reduce the amount of litter generated from the island. However, the persistence of plastic in particular means that even if global discard rates also slow, the total amount of plastic in the ocean will continue to rise.

Legislation:

National Protected Areas (Marine Protected Area) Regulations, 2021

MARPOL

The Environmental Protection (Overseas Territories) Order (1988)

The National Protected Areas Regulations, 2014

The Litter Ordinance, 1971

Actions:

Conduct regular litter clearance

Ascension Island public engagement campaign

Effectively enforce regulations

Threatens achievement of Objectives:

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

2a. People living on Ascension have access to recreational and fishing opportunities in the MPA that are equitably shared and enjoyed by the community

Description: There is no industry or agriculture on Ascension and no rivers or streams to transport land-based pollution to the sea. However, there are point source discharges from the island and the potential for large-scale run off events following heavy rain.

Almost all of the fresh water on Ascension is produced by reverse osmosis and the outfalls from the desalination plants release hypersaline water into the ocean at English Bay and Pan Am Beach. The cost of producing water makes it a scarce and valuable commodity and so most of the wastewater produced on the island is collected and delivered to households for use in their gardens and under normal circumstances no wastewater enters the ocean. The exception is periods of intense rainfall, which overwhelm the system and cause wastewater to be discharged into the sea at the southern edge of Clarence Bay. Wastewater from the USAF Base is treated at a wastewater facility before being discharged into the ocean close to Pam Am beach.

Food waste from the USAF Base is disposed of directly into the sea at Springer’s Beach. This is sorted to remove plastic wrappings and paper napkins resulting in waste composed mainly of meat, dairy and plant material.

Periodically Ascension experiences extremely intense rainfall well beyond the capacity of the limited natural and artificial drainage systems. The result is high levels of run off entering inshore environments. This can contain chemical residues from roads and urban areas as well as wastewater effluent (as described above), but the greatest threat comes from erosion of the unconsolidated volcanic dust and clinker that make up the surface layer of much of the island.

Assessment of the scale of threat: The desalination outflows at English Bay and the USAF Base release 12-13m³ and 27-34m³ of hypersalinated water an hour respectively. The small volume of effluent and rapid dilution once it enters the sea mean effects are very localised. For example mixing of the Encompass effluent with 5000m³ of seawater would decrease the salinity of the outflow to less than 0.1% above background levels meaning that in water depth of 5m the impact of the discharge would be negligible beyond an area approximately 30m by 30m adjacent to the outflow pipe.

The civilian wastewater treatment plant at Georgetown is in urgent need of repair. There may already be some leakage from the outdated piping into Clarence Bay and there is a high risk of catastrophic failure if the plant is not replaced. Testing of the effluent from the plant is undertaken weekly to ensure it is safe for use on domestic gardens, but to date there has been no monitoring of leakage or potential impacts on the adjacent marine environment.

No data are available on the amount or composition of waste food from the USAF mess discharged at Springer’s Beach. The high abundance of black triggerfish and their wide feeding habits mean that most of the waste is quickly consumed. However, there could be an accumulation of oil or chemical residues and this concentrated input of nutrients could alter the local ecosystem function.

Major sediment run off events are rare. There are no formal records, but speaking to long-term residents of the island suggests they seem to occur at a roughly 1 in 20-30 year frequency with smaller run-off events occurring approximately every five years, including in 2020. When run off events do occur, the high sulphur content of the dust will affect water chemistry and lower pH, and the sediment itself will reduce light penetration when suspended in the water column and smoother benthic organisms as it settles out. People who have witnessed such events describe the sea as turning red and report mass fish deaths in the following days. Irving (1989) reports seeing the impact of a heavy rain event in 1984 when rock pools were found to be smothered in sediment and dead colonies of Favia corals were recorded during surveys carried out in the following year.

Pan Am beach during heavy rains in March 2020. Sediment run off into the bay is clearly visible.

Species/habitats at risk:

Rocky reefs, sandy substrate, rhodolith beds, intertidal pools, pelagic waters around seamounts, benthic habitats on seamounts, epipelagic ocean, mesopelagic ocean, bathypelagic ocean, hydrothermal vents, lower slopes of Ascension Island and seamounts, flat abyssal plains

Green turtle, land crab, rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, Galapagos shark, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan, yellowfin tuna

Predicted future trend: The runway reconstruction project planned for 2020-2022 will result in a 25% increase in Ascension’s population and a consequent increase in food, waste water and drinking water demand. This increase will be temporary, but the runway reconstruction could lead to a sustained increase in the working population and visitor numbers on Ascension and so result in a long-term increase in discharges.

Legislation:

The Environmental Protection (Overseas Territories) Order (1988)

National Protected Areas Ordinance, 2003

Actions:

Implement Marine Pollution Control Plan

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

2a. People living on Ascension have access to recreational and fishing opportunities in the MPA that are equitably shared and enjoyed by the community

Description: The Island’s requirement for aviation fuel and diesel means fuel is delivered by sea tanker, which is then pumped to shore using mobile floating pipelines. Civilian fuel deliveries are organised by the company Encompass and come ashore at English Bay close to their fuel storage tanks. Deliveries for the UK Ministry of Defence (MOD) are piped ashore at the Georgetown pier and then pumped through overground pipelines to fuel storage tanks at Catherine Point, and then onwards to a bulk storage installation at the military base.

Vessels transiting the Ascension MPA will also have fuel tanks and a small number will be bulk carriers transporting fuel or other hazardous chemicals. These will all pass at least 12NM from the island and there are no physical obstacles in this part of the ocean.

Assessment of the scale of threat: The volume of fuel arriving on vessels, being pumped ashore and stored close to the coast means that any spill could be locally catastrophic for the inshore marine environment. This could include significant impacts on seabirds and green turtles if a spill occurred during their mating and nesting period. However, the likelihood of this happening is low due to the stringent procedures followed by Encompass and the MOD during fuel delivery, their pollution response capability and the bunding of storage tanks. Damage to the MOD’s overland pipeline that runs parallel to the coast for 5kms is perhaps the more likely source of a spill, however this is regularly inspected and measures are in place to prevent a collision and rupture. No oil spills have ever been recorded on Ascension in the many decades over which fuel has been delivered by this method.

Leakage from other vessels could pose a greater risk and the Ascension Island Government currently has no emergency pollution response capability to deal with such incidents. Leakage in the offshore areas of the MPA would have less impact due to the rapid dilution and dispersal that would occur there. Inshore areas are again most vulnerable, but the volume of vessel traffic within 12NM of the island is very small meaning the likelihood of an incident is low even if the impact would be severe.

Species/habitats at risk:

Sandy beaches, sea cliffs, rocky reefs, sandy substrate, rhodolith beds, intertidal pools, anchialine pools

Green turtle, land crab, Ascension frigatebird, masked booby, sooty tern, rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, Galapagos shark, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, shrimps of the anchialine pools, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan, yellowfin tuna, Atlantic blue marlin, wahoo

Predicted future trend: Significant increases in the volume of fuel supplied to the island, which determines the underlying risk of a spill incident, are expected once the runway is repaired and Ascension resumes its role as a refuelling site for the South Atlantic Airbridge. Further increases would only be expected if there is a shift in the military missions of the MOD or the USAF based on the island. Already stringent procedures for transferring fuel are only likely to become tighter and the development of an AIG capacity to deal with spill incidents will decrease the scale of any impact.

Legislation:

MARPOL

MOD, USAF and Encompass have protocols in place covering their vessels and fuel delivery operations

Actions:

Implement Marine Pollution Control Plan

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

Description: Sound waves travel well in water and noise created by human activities can impact a large area of the ocean. Engine and propeller noise from shipping traffic is the major source of noise pollution in offshore areas. Other sources include low frequency sonar used in exploratory surveys and submarine detection and high frequency sounds used in acoustic tracking studies. In inshore areas, vessel noise is also the major source of noise pollution, but any coastal development or activity could create disturbance.

The sensitivity of species to noise pollution has been most intensively studied in cetaceans where it has been shown to disrupt feeding and social behaviours and to contribute to stranding events. However, many other groups are also affected and a review found records of impacts on 55 marine species (Weilgart 2008).

Assessment of the scale of threat: No direct measurement of noise levels in the Ascension MPA has been carried out, but compared to other parts of the Atlantic Ocean, there are very few vessels in the MPA since it does not lie on any major shipping lane and the prohibition on commercial fishing means very few fishing vessels even transit the area. No mineral extraction is allowed in the MPA and exploratory surveys for this industry would not be permitted. Some scientific research using sonar has been carried out over the last four years, but the frequency and duration has been very limited and this activity is controlled through the AIG research permitting scheme.

Disturbance in inshore areas is slightly more concentrated with approximately 20 resupply vessels, three cruise ships and 20 yachts visiting the island each year in addition to the approximately 10 small boats based on Ascension and the barges used for ship unloading every six to eight weeks. The impact is largely localised to the area around the Pierhead and Clarence Bay where most boats are moored and unloading activity takes place.

Species/habitats at risk:

Rocky reefs, green turtle, humpback whale

Predicted future trend: There are no indications that noise pollution levels will change significantly from current levels.

Legislation:

The Harbours Ordinance, 2005

Research permit system controls scientific activity that could generate noise.

Actions: Control developments in the MPA

Threatens achievement of Objectives:

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1e Maintain size distribution and age at maturity of species in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

Description: Only a small proportion of non-native species survive and become damaging when introduced outside of their natural range, but those that do can profoundly disrupt marine ecosystems through predation, competition or uncontrolled growth smothering native species. The spread of non-native marine species is closely linked to the movement of shipping around the world with vessel hulls and ballast water the most common routes of spread.

Pelagic ecosystems are at lower risk because of the natural degree of mixing caused by ocean circulation and the highly mobile nature of many pelagic species. Shallow water and benthic ecosystems have evolved in greater isolation and so are more vulnerable to invasion from outside.

Assessment of the scale of threat: In contrast to terrestrial habitats on Ascension where over 95% of species are thought to be introductions, non-native species have not been recorded in Ascension’s marine environment. The relative lack of vessel movements, Ascension’s isolation and the high abundance of grazing black triggerfish all combine to reduce the risk, but there are still pathways by which non-native species could reach the island.

Ascension is visited by approximately 40-50 vessels per year including resupply vessels, cruise ships and yachts. Those coming from the UK pose a relatively small risk as they originate from much colder waters and it is unlikely any species found in UK ports would adapt well to the seas around Ascension. A greater risk is presented by supply vessels from St Helena, Florida and the African coast and from yachts that travel across the tropical and subtropical Atlantic.

An horizon scanning exercise carried out by the Scottish Association of Marine Science as part of the Improving biosecurity in the SAUKOTs through Pest Risk Assessments Project identified the following species as presenting the greatest risk to marine ecosystems on Ascension based on their likelihood of arrival, establishment and damaging impact:

• Mediterranean mussel (Mytilus galloprovincialis)
• Pacific oyster (Magallana gigas)
• Asian green mussel (Perna viridis)
• Bivalva (Semimytilus algosus)
• Orange cup coral (Tubastraea coccinea)
• Ascidian (Ciona robusta)
• Lionfish (Pteriosis miles)

Vessel hulls and the discharge of ballast water are the most likely route of introduction for all the species listed except lionfish. The most likely pathway for lionfish to arrive on Ascension is by being discarded from an aquarium. There are no saltwater fish kept on Ascension but some superyachts have onboard aquaria that are reportedly refreshed during voyages. Superyachts are rare visitors to Ascension and the likelihood of introduction seems low, but the devastation caused by this species around Caribbean islands makes it a high risk.

Species/habitats at risk:

Rocky reefs, sandy substrate, rhodolith beds, intertidal pools, anchialine pools

Rock hind grouper, moray eel, glasseye snapper, spiny lobster, black triggerfish, endemic inshore fish species, Ascension goby, common octopus, rock oyster, rustic rock snail, white-striped cleaner shrimp, shrimps of the anchialine pools, Ascension lightfoot crab, black longspined and rock boring oyster, bearded fireworm, corals, sponges, coralline algae, bryozoan

Predicted future trend: The introduction of tighter biosecurity regulations will reduce the threat, but this will be against a background of increasing global shipping movements and climate change that will both act to increase the risk of non-native species arriving on Ascension.

Legislation:

The Biosecurity Ordinance (2020)

The Ballast Water Management Convention

Actions: Biosecurity controls

Threatens achievement of Objectives:

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1g No reduction in the extent or condition of key habitats

Description: There are no marine non-native species currently recorded from Ascension’s MPA, but terrestrial non-native species have an impact on the success of seabird, green turtle and land crab populations. This occurs through the encroachment of shrub species that reduce the area of available nesting habitat and provide cover for non-native predators such as rats (Rattus rattus), mice (Mus musculus) and myna birds that feed on eggs and hatchlings.

Assessment of the scale of threat: Turtle nesting beaches and coastal plateaus used by breeding seabirds are being encroached by woody shrubs such as Mexican thorn (Prospsis juliflora), tree tobacco (Nicotiana spp.) and guava (Psidium guajava) and by annual plants such as the Mexican thistle (Argemone mexicana). These make the habitat unsuitable for turtles and seabirds that rely on loose sand and clear ground to lay their eggs. Historical photos of Ascension demonstrate the rapid spread of non-native shrubs across the island and without active and sustained control it is likely that the main beaches would become densely vegetated within a few decades. The main seabird colonies are on the southern and eastern side of the island where shrub encroachment has been slower, but the pressure on these areas is increasing as non-native plants expand their range into the protected areas.

Aerial photographs showing the spread of Mexican thorn scrub to the rear of Long Beach, the most important green turtle nesting beach on Ascension. Clearance efforts in the area adjacent to the beach outlined in red were undertaken between 2015 and 2018.

The potential impact of non-native predators on seabirds was demonstrated by feral cats. Historically these prevented many seabird species from breeding on the mainland until a project led by the Royal Society for the Protection of Birds eradicated them from Ascension in 2004. The return of breeding frigatebirds and boobies to the mainland since 2004 suggests that the remaining predation from rodents and myna birds is not as significant as the cats were. However, isotope and stomach content analysis has shown rats consume the young of both seabirds and turtles (Brown 2019). It is unclear whether the rats are killing the chicks or just scavenging the remains of those that died from other causes, but it could be having a significant impact on sooty terns in particular.

Species/habitats at risk:

Sandy beaches, coastal plateaus, green turtle, land crab, Ascension frigatebird, masked booby, sooty tern

Predicted future trend: The direct threat of non-native species on coastal nature reserves has decreased through targeted control efforts and these will be continued in future years. However, the abundance of non-native species across the rest of Ascension is likely to increase due to insufficient resource to tackle them outside of the protected areas. As a result, the pressure on the borders of the nature reserves is likely to increase and any reduction in control efforts within the reserves will lead to rapid encroachment.

Legislation: The Biosecurity Ordinance, 2020

Actions: Non-native species control

Threatens achievement of Objectives:

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1g No reduction in the extent or condition of key habitats

2d. Ascension is recognised as a world leader in the responsible management of sports fishing and ecotourism; these activities have no negative impact on the behaviour or population size of protected species

Description: People living on Ascension and visitors to the island enjoy swimming, snorkelling and diving as well as walking on the beaches and coastal plateaus. They may inadvertently harm wildlife through the disturbance they cause to an animal’s natural behaviour. Examples could include the abandonment of nesting or mating attempts, higher energy expenditure or reduced feeding opportunities due to avoidance behaviour or the cumulative effects of elevated stress levels.

People can also unintentionally cause physical damage to species and habitats through their recreational activities. Divers trailing equipment can damage sedentary benthic organisms and reef structures. Walkers can crush the eggs of ground-nesting seabirds.

Assessment of the scale of threat: The greatest risk of disturbance on Ascension is to nesting green turtles as they are a major tourist attraction and the nesting beaches are very accessible. Even quite low levels of disturbance can lead female turtles to abandon nesting attempts and return to the ocean. In the past there have been incidents of people attempting to ‘ride’ turtles on land and in water, though this is strictly forbidden under the Wildlife Protection Ordinance. Smaller numbers of people visit the important bird breeding areas on the main island (Letterbox Peninsula and Wideawake Fairs), but there is still the potential for disturbance here particularly at sensitive times when birds are incubating eggs or chicks are very young.

Diving, swimming and snorkelling are all popular past times on Ascension and are concentrated in the north-west quadrant of the coast. There will inevitably be interactions that disturb or damage individual animals, but the small island population and limited number of tourists mean this is not a threat likely to cause a population-level impact on any inshore species. Information signs are present at the most popular sites providing guidance on how to avoid disturbance and explaining the laws in place to protect wildlife.

Controlling tourist impacts is relatively easy at present since tourist numbers are low due to the poor air access and most tourists arrive as part of organised cruises that can be managed. Restoration of direct flights to the UK could result in an increase tourist numbers and greater impacts in the future (Millington 2019).

Species/habitats at risk:

Sandy beaches, coastal plateaus, rocky reefs, sandy substrate, rhodolith beds, intertidal pools, anchialine pools, green turtle, land crab, Ascension frigatebird, masked booby, sooty tern

Legislation:

Wildlife Protection Ordinance, 2013

National Protected Areas Ordinance, 2003

Predicted future trend: The restoration of the South Atlantic Airbridge route through Ascension and improved marketing of the island’s sports fishing and ecotourism opportunities could result in an increase in visitor numbers from current levels, though they are likely to hit a ceiling at a predicted 600 tourists per year. Whether this happens and to what degree will depend on the ‘Future of Ascension’ discussions that will determine how the island operates.

Actions:

Tourism development strategy

Guidance and regulations for sports fishing and ecotourism

Ascension Island public engagement campaign

Threatens achievement of Objectives:

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

2g Future developments are assessed and designed to be compatible with the conservation objectives of the MPA

Description: Development can include a broad range of activities and the National Protected Areas Ordinance, 2003, define it as: any change in use of land, the erection of any structure and the carrying out of any drainage, dredging or sewerage scheme and any other activities prescribed by the Governor by order. Damage can be caused during the construction or operation phase of a development and can include direct damage and loss of habitat, water contamination and disturbance to species.

Assessment of the scale of threat: Development within the MPA requires permission from the Administrator following an environmental impact assessment. There is little development pressure on Ascension due to the small population size and lack of industry, but modifications to the pier, waste water treatment facilities, fuel installations, desalination plants and moorings could all be necessary and have the potential to damage inshore habitats. The efficient working of the pier also requires regular dredging to accommodate the draught of the unloading barges. If sea levels and extreme storm events continue to increase, then some coastal protection work may be necessary to protect infrastructure around Georgetown and English Bay. Other forms of development are harder to foresee ever being proposed on Ascension, but cannot be ruled out over future decades.

Proposals for development in offshore areas are highly unlikely due to the logistical difficulty and cost. Deep sea mining is developing as an industry and is discussed specifically in the mineral extraction section. New subsea communication cables are being proposed in the Atlantic, but there are currently no plans for these to come close to Ascension. There are no other types of offshore development on the horizon and there is no immediate threat to this part of the Ascension MPA.

Species/habitats at risk:

Sandy beaches, rocky reefs, sandy substrates, rhodolith beds, green turtle, land crab, corals, sponges, coralline algae, bryozoans

Predicted future trend: There is nothing to suggest the current low level of development pressure on Ascension’s coastal and marine environments will increase. In addition to ongoing maintenance of the Georgetown Pier, the only potential new developments on the horizon are the laying of new subsea communications cables.

Legislation:

National Protected Areas Ordinance, 2003

Harbours Ordinance, 2005

Actions: Control developments in the MPA

Threatens achievement of Objectives:

1a. No loss of species and no reduction in species abundance or ecosystem complexity in offshore areas

1b. Proxy objective: Surveillance, compliance and enforcement regime effectively detects all known threats to offshore ecosystems

1c. No loss of species and no reduction of species abundance or ecosystem complexity in inshore areas

1f No loss of genetically distinct sub-populations from inshore or offshore areas

1g No reduction in the extent or condition of key habitats

2g Future developments are assessed and designed to be compatible with the conservation objectives of the MPA

Description: Mining activities and mineral extraction can cause significant damage to marine habitats. Sand extraction and dredging result in the loss of beach and inshore habitats and could destabilise the natural erosion and deposition cycles meaning the impact of the activity would be felt over a much greater area than the immediate extraction site.

Deep sea mining is still in its infancy, but two licences for exploratory mining have now been granted in Papua New Guinea and Japan (Miller et al. 2018). Concerns have been raised about the environmental damage that could be caused by the industry through the destruction of deep sea habitats, release of sediment, alteration of water chemistry and disturbance. Mining activities in active geological areas could also potentially trigger earthquakes or the release of magma.

Assessment of the scale of threat: Mineral extraction from the MPA is not permitted under the National Protected Areas Ordinance, 2003. This applies to the entire MPA and so any sand extraction from beaches below the high tide mark, mining in the inshore environment or deep sea mining would be an illegal activity. Dredging in the Harbour Area (from Catherine Point to North Point) is permitted to enable the pier to be maintained, but the dredged material cannot be removed from the MPA.

There is a high likelihood of very small scale, illegal sand extraction taking place from Ascension’s beaches. There has been a long tradition of using beach sand on the island and education and clear legislation has failed to stop the practice entirely. However, the use of any large machinery to extract sand will quickly be noticed, so any illegal activity will be very limited and unlikely to cause significant damage.

The geology of Ascension is such that inshore areas are not thought to contain minerals of any worth, meaning there is little incentive to undertake illegal mineral extraction. Ascension would also not be an attractive location to develop deep sea mining because of the relatively small extent of the predicted deposits, very deep water and remote location, so there is unlikely to be any illegal activity. Globally the most valuable deep sea mineral deposits are associated with areas of high tectonic activity and hydrothermal vents, some of which do occur in Ascension’s EEZ. However, the Mid-Atlantic Ridge close to Ascension is one of the slowest areas of spreading seafloor and vent fields are therefore smaller than in other regions. It is highly unlikely that manganese nodules, one of the resources attracting most commercial interest, are found in Ascension’s waters (La Bianca et al. 2018).

Beyond the boundaries of the MPA, any deep sea mining in the high seas would be subject to the International Seabed Authority’s (ISA) Mining Code, backed by the UN Convention of the Laws of the Sea (1982). This requires assessment and the issuing of contracts for all deep sea mining activity in areas beyond national jurisdiction. Large-scale mining activity close to the boundary of the MPA does have the potential to damage natural features within the MPA and these should be considered by the ISA under their mandate to protect the marine environment.

Predicted future trend: Deep sea mineral extraction is likely to grow as an industry in future years as technology develops and deposits of valuable resources in the deep ocean are mapped. However, Ascension’s location, water depth and geology mean that there is unlikely to be any increase in pressure to carry out this activity in the MPA.

Species/habitats at risk:

Sandy beaches, sandy substrate, hydrothermal vents, lower slopes of Ascension Island and seamounts, flat abyssal plain, green turtle, land crab, Ascension goby, vestimentiferan tubeworm, rimicaris shrimp, bathymodiolus mussels, grenadiers

Legislation:

National Protected Areas Ordinance, 2003

Harbours Ordinance, 2005

International Seabed Authority treaties on deep sea mining

Actions: Monitor new threats to the MPA habitats

Threatens achievement of Objectives:

2d. Ascension is recognised as a world leader in the responsible management of sports fishing and ecotourism; these activities have no negative impact on the behaviour or population size of protected species

3a The Ascension Island MPA becomes a world-renowned site for the scientific study of marine ecosystems

3b Ascension becomes an active and influential member of international networks of MPA managers, and initiates and participates in collaborative projects

3d The Ascension MPA and the conservation and scientific work being undertaken reaches a global audience leading to increased political and financial support

4d Human and financial resources are secured to deliver effective management

Description: Ascension’s remoteness may be a key factor that has contributed to the wealth of its marine life, but it also presents challenges for the MPA’s socio-economic and governance objectives.

At the time of MPA designation in August 2019 the only civilian route to Ascension was a monthly flight from St Helena, which connects with a service to South Africa. It is anticipated that, following the Ascension runway being repaired in 2022/23, the South Atlantic Airbridge that connects Ascension with the UK and Falkland Islands will resume.

The governance structure of Ascension is currently being reviewed by the UK Government with a decision expected shortly. The MPA will be part of any future scenario, but tighter restrictions on access to the island could be introduced if Ascension becomes a fully military island. This could affect the ability of non-military personnel to access the island for research or recreation.

Assessment of the scale of threat: Many of the normal routes for generating financial benefits from an MPA, such as tourist spend and permit fees, are reliant on visitors attracted to pristine marine environments. The MPA Financial Strategy estimates that £8,500 could be generated annually from a tourist levy and tour fees and a further £15,000 from sports fishing licences. These would be part of a wider economic benefit to the island estimated at £609,000 per year for tourism, but this would only be realised if good civilian air access to the island is possible. The suspension of the Airbridge has demonstrated that no tourism or sports fishing sector will exist without improved air access.

Predicted future trend: Reconstruction of the runway, due to be completed in 2022/23, should improve access in the short-term. Decisions on the ‘Future of Ascension’ could result in long-term access becoming significantly more or significantly less difficult depending on the model chosen.

Actions:

Tourism development strategy

Develop Ascension as a scientific research hub

Threatens achievement of Objectives:

3c Every person on Ascension is aware of the MPA and its purpose

3d The Ascension MPA and the conservation and scientific work being undertaken reaches a global audience leading to increased political and financial support

4b Key stakeholder groups are effectively engaged in MPA governance structures and benefit equitably from management decisions

4d Human and financial resources are secured to deliver effective management

Description: The Ascension MPA will rely on people living on the island contributing to management decisions through the oversight committees and public consultations, complying with the regulations and volunteering their time to help with activities.

Financial and technical support for the MPA will be needed from the UK Government and international NGOs. Their focus on this issue and their ability to secure funding from government budgets or donations is partly the result of high public awareness and consequent political interest in marine protection. Research activity is also driven by the funding priorities of research councils, private trusts and NGOs, which are similarly influenced by the perceived priorities of the public and politicians.

Assessment of the scale of threat: Without local support for the aims of the MPA, enforcement of the regulations and the delivery of some MPA actions will be exceptionally challenging. Beach cleans, inshore data collection and the response to any pollution event will require the cooperation of people and organisations across the island to be effective. More fundamentally, the entire legitimacy of the MPA could be questioned if there is no representation from the local community on the oversight committees and good engagement with consultations. Currently there is support for the MPA on Ascension, but this will only be sustained if a sense of ownership is built and benefits flow to the island.

Ascension is reliant on external funding to manage its MPA, international initiatives and cooperation to counter illegal fishing and the interest of the scientific community to realise the global value of the MPA. While none of these are directly dependent on members of the public, all rely on political prioritisation that ultimately is directed by the public. It would not be immediate, but a significant reduction in public support for marine protection could lead to an MPA without the means to carry out any effective management.

Predicted future trend: Global interest in environmental issues and marine conservation have been increasing consistently for many decades. This looks likely to continue particularly as the impacts of climate change become more tangible. However, sharp rises in interest due to particular events (e.g. the ‘Blue Planet Effect’) are harder to predict and likely to be short lived.

Actions:

Ascension Island public engagement campaign

Global public engagement campaign